edited by MIRIAMC. NAGEL Avon High School Avon. CT 06001
It's a Question of Safety Mlrlam C. Nagel A w n High School
Awn. CT 06001
The secondary school chemistry teacher is expected to he well versed and up-to-date in general chemical principles, t o he informed about current safety practices, to maintain chemical supplies and laboratory equipment, t o prepare prudent purchase lists, t o meet all m-curricular obligations, and to keep the peace with administrators, parents, and students. The teacher is expected to keep current motivational lesson p l a n e a n d to follow them faithfully. The same teacher probably has to set up and clean up five laboratory classes or more each week, to set up and use enlightening and safe demonstrations, to assemble and use appropriate audiovisuals and, now, software, too. Obviously, safety is not the only concern of the chemistry teacher, but it has to he a prime responsibility. An explosion, a fire, or a hazardous chemical spill can he instantly devastating. No list of safety recommendations can cover every situation, hut there are some basic questions teachers should ask themselves regularly to maintain their preparedness. How Well Informed am I on Safety? The consequences of heating potassium ehlorate in an unclean test tube should not have t o he rediscovered in the lab by every generation, yet this well-documented explosion hazard is still severely injuring students.' The teacher has the prime responsihility for selecting safe experiments. No teacher should feel complacent about safety education. There is alwavs a need t o be better informed. Sources of curshould he read rourent information such an TI(&JOURNAL tinelv. There are also eood texts available. A list of manv of the Eurrent safety books can be found in the Lah safety Supply ~ a t a l o gThe . ~ ACS publication "Safety in Academic Chemistry Laboratories" is recommended ~ e a d i n gSeveral .~ states have prepared safety information for their teacher^.^ Have you checked with your state department of education lately? Do I Instruct Students about Safety In an Appropriate Manner? That word appropriate is a tightrope. Students have to understand the~c&~onsneeded i h i l e ihey work in a lahoratory. Use of proper safety equipment is essential trnining for life. But ntudenis are as varied as anv other collection of 2&30 people. What impresses one student might he ignored by another, or paralyze a third. One conscientious teacher made a point t o mention t o a fair-skinned, red-haired boy with obvious adolescent skin problems, that he should avoid touching his face while working with chemicals and he a little extra careful to wash well afterward. His response was to bring long, surgical-type rubher eloves t o his next lab. and. subseauentlv. he spent a eood portion of each periodlust ietting ready towork: ~ i s p e ' i f o r mance would have been impressive on a TV soap opera. The teacher's well-intentioned advice practically dkstioyed the student's ahility to function in the lab. Another boy was so impressed by the instructions on lab
1012
Journal of Chemical Education
safety that he went out and bought himself a pair of safety goggles to wear when he crawled under his car so foreign bodies could not fall into his eyes. That is the kind of safety habit teachers wish they could always instill. How Well Do I Plan for Safely? With the multitudinous other respomihilities of a secondary school chemistry teacher, a checklist for safety is helpful. Do you regularly 1. try experiments and demonstrationsbefore using them with students? 2. check equipment ahead of time? 3. set up only the chemical needed, well labeled and usingeolor d i n g to minimize the potential for mistakes? 4. check storage shelves for:5 misplaced chemicals-are incompatibles properly stored? overcrowding on shelves? any loose or damaged labels? any old, unused chemicals? any dangerous chemicals that should be removed? 5. inventory before reordering to avoid undesirable sur. supplies .. plus? 6. review waste disoosal orocedures and oolicieaP 7. check that all fahilitie; are in good woFking order: eyewash and safety shower? hood and room ventilation? fire extinguishers? shutoffs for electricity,gas, water? sink drains? labeled disposal containersin place? An overworked teacher in a relatively new lab had only superficially checked the student sinks for several months. One dav the teacher workine in the room below the lab heard ~~~~" water dripping, looked up, and saw the ceiling tiles bulging with water. After an ureent call the orohlem was investieated. During the remodeling, the waste pipe for one sink hab not been hung properly, and the sagging pipe was slowly pulling the sink under the lah table. Noone noticed that all the water was no loneer eoine into the sink. Some of it was splashing over the edge i f tKe s&k under the bench and seeping into the ceiling of the room below. Most teachers assume the fire extinguishers are ready for use in the lab when they are in their proper places on the wall. I t is wise to look a t the dates on which the extinguishers were last checked. That precaution, unfortunately, d o e not always guarantee a ready-to-use extinguisher. Several years ago custodians hastily took a large extinguisher from the chem lab t o use outdoors on a brush fire adjacent to the parking lot. When the emergency was over, they replaced the fire extin~~~
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CHAS Notes, 1 [3]. 2 (MayJune 1982) (Published by the ACS Division of Chemical Health and Safety.) Lab Safety Supply, 3430 Palmer Drive, P.O. Box 1368,Janesville, W153547 ... ... ..
American Chemical Society, 1155 Sixtee& St. N.W., Washington, DC 20036. PA: Bureau of Curriculum Services, Pennsylvania Department of Education, P.O. Box 911. Harrisburg. PA 17108;NC: Division of Science Education, State Department of Public Instruction, Raleigh, NC 27611. Flinn CataloglReference Manual, Flinn Scientific,Inc., P.O. Box 231. Batavia, IL 60510.
wisher to its place on the lab wall. A few weeks later the lab teacher had asmall fire at the demo table. Trying to make a safty point, the teacher grabbed the empty extinguisher. A lesson-was learned, but not the one intended. Fortunately, the fire was easily smothered by other means. DOI Accept My Responslblllty to Supervise Personally All Lab Activltles?
The teacher is responsible for all activities and all persons in the laboratory. Supervision should not be delegated to any unqualified person. The use of student aides has to be limited to closely supervised activities. No teacher should fmd himself or herself in the position of frantically asking "How did it happen?" while administering first aid to a student burned with concentrated acid while workine without direct suDervision in a prep area. Yet ~ u c han incident did happen. Student aides can be verv. heloful . with routine cleanuo of laboratory equipment. Some can make minor repairs. Re-
stocking student supply bottles with low-risk chemicals from stock bottles and labeling student supply hottles are also time-consuming tasks that aides can do well. Students can prepare specific concentrations of solutions if none of the chemicals are high-risk reagents. Dilution of concentrated acids or bases should not be considered a task for student aides. One teacher asked a good student aide to prepare a specific concentration of sodium hydroxide using pellets. The student was using an automatic stirrer in a prep room by himself when he saw his time was short and turned the stirrer up too high. As luck would have it, the student was small and when the solution splashed out he was spattered on the face. Fortunately, he did rinse his face, but did not tell anyone about his accident. A few days later another teacher asked about the pink spots on his skin and he confessed. The boy should never have been in a situation to be injured in that fashion. A much more serious injury could have resulted from the lack of supervision.
Volume 61
Number 11
November 1984
1013
